1. Field of the Invention
This invention relates generally to measuring and testing. It relates in particular to a device for the wear testing of fabrics, especially carpets.
2. Prior Art
Fabrics such as carpets are expected to have good appearance-retention over their useful life. In addition, static-protected constructions are expected to protect against the accumulation of undesirably high charges of static electricity over their useful life. For these and similar reasons, many fabric constructions are routinely subjected to wear under actual service conditions, in order to determine the durability of various properties, thereby affording a prediction of the suitability of the construction in certain proposed applications.
Because of the lengthy periods of time often required for wear testing under actual service conditions (e.g., the time required to achieve 100,000 actual walkons of a sample of carpet -- as determined by electronic counting devices -- may be as long as 1-3 years), devices achieving accelerated fabric wear have been earnestly sought after by the industry for quite some time.
Consequently, many expedients have been proposed, and a number of devices embodying these expedients have been manufactured and sold. As an example, one such device comprises a metal cylinder having the fabric sample to be tested affixed to the inside surface of the cylinder. Four aluminum bars, each 2 inches square by 6 inches long and coated with a tough polymeric material, are placed inside the cylinder to tumble randomly and produce an abrasive action on the fabric sample as the cylinder is caused to rotate about its longitudinal axis. Notwithstanding the efficacy of this device and similar devices of the prior art (e.g., tests show a reasonably good correlation between in service stroll tests conducted on samples of carpets which were subjected to 85,000 walkons and like samples which were subjected to six hours abrasive action in this device), they are found wanting, -- e.g., in that the carpet constructions are not worn in a manner which closely approximates that effected by the shoe of a human. For example, the "beating" abrasive action of many of the prior art devices makes it impossible to accurately assess the changes in shade in a traffic pattern, which would result when a yarn tuft is first flexed in one direction and then in the opposite direction as the foot of a human contacts the carpet sample and then leaves it.